This prospective study included 67 adult patients with low, intermediate or high malignancy degrees of non-Hodgkin' s lymphomas according to the Working Formulation. Patients with or without anti-HIV antibodies in the serum were considered. All patients were submitted to neurologic evaluation, and 63 of them to examination of the cerebrospinal fluid (CSF). Patients presenting neurologic signs and symptoms were 42 (62.7%). Neurologic findings and CSF changes were correlated. The association of localized thoraco-lumbar pain and CSF changes (presence of neoplastic cells, increased protein concentration and/or increased gamma globulin content) was statistically significant, as the association of abnormal muscle strength in the lower limbs and CSF changes in patients without HIV antibodies in the serum. Cranial nerve dysfunction (III, IV and VI cranial nerves) correlated with the finding of neoplastic cells in the cerebrospinal fluid.